/srv/irclogs.ubuntu.com/2014/04/01/#ubuntu-kernel.txt

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tjaaltonhuh?04:04
tjaaltonRAOF: i don't recall seeing that before04:08
RAOFtjaalton: Hm. I thought you were talking on #intel-gfx about some hardware context not being there?04:11
tjaaltonwwll bdw has bugs, but i bet this is with something older04:14
tjaaltonhttps://bugs.freedesktop.org/show_bug.cgi?id=75723 it seems04:24
ubot2Freedesktop bug 75723 in Drivers/DRI/i915 "(regression since Linux 3.14?) brw_get_graphics_reset_status: Assertion `brw->hw_ctx != ((void *)0)' failed" [Normal,New]04:24
RAOFAh.04:27
tjaaltonlove how it's been opened a month ago with zero interest04:33
ppisatiyo05:40
tjaalton µ’06:58
smbn'?07:08
tjaaltoncat07:09
tjaaltonexplains all typos from me07:09
smbheh :)07:10
smbLuckily mine stays outside (unless I fail to prevent him) normally07:10
amitki read that as "micro tic" which is close to a router company "microtik" or a new way to wave on IRC ;)07:16
tjaaltonwhatever works :)07:23
* apw yawns07:47
smbapw, Caution there are giant bees approaching from Australia07:53
sorensmb: Yet he comes back?07:55
sorensmb: (re: The cat, not the bees)07:55
smbsoren, Ah, I was wondering. Yes, he does. Apart of being his can opener, he thinks he has to inspect all rooms from time to time07:56
sorensmb: Interesting.07:57
sorensmb: I just thought cats were smarter than that. If he wants to go out, but coming into your house means being prevented from going back out, I'd assume he'd not come back.07:57
sorensmb: That's the argument I use with my wife for letting our cat out whenever he wants. :)07:57
smbsoren, He is smart enough to actually make use of many people. So he isn't owned by anyone but gets treats everywhere07:58
smbIts a shared cat07:59
sorensmb: Clever.08:01
erle-how can i monitor actual cpu frequency (as opposed to nominal cpu steps, e.g. while running overclocked or using turbo mode)10:40
apwerle-, sudo cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq has instantaneous levels10:43
erle-apw, that one only tells me nominal states10:44
erle-but i found the solution in the meanwhile10:44
erle-from packe linux-tools the command turbostat10:44
apwok good10:44
ogra_i thought you need to look at scaling_cur_freq for the realtime data 10:46
erle-ogra_, both only display the steps of 800,1600,2400 and 320010:47
erle-ogra_, i run at 3712 (highest regular step) and 4176 (turbo)10:48
erle-bios tells me10:48
erle-i want to know whether linux uses the turbo10:48
erle-(AMD turbo10:48
erle-)10:48
erle-does anybody here have experience with amd turbo core?10:57
erle-i disabled 4 of 6 cores in bios and overclocked, because i want to run a hard single-threaded simulation10:58
erle-turbo core requires half of cores to be idle10:58
erle-do disabled cores count as idle?10:58
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ogra_is there a way to dynamically raise the ringbuffer size ? i try to debug some boot stuff, but by the time i can read dmesg or kern.log the buffer is already overwritten14:14
apwogra_, yeah there is a kernel parameter for that14:16
ogra_remember which ?14:16
henrixogra_: kernel-parameters.txt talks about log_buf_len14:17
henrix(never used it myself)14:17
apwlog_buf_len = bytes i think14:17
ogra_henrix, thanks !14:18
ogra_will try 14:18
rtgogra_, no spaces around the ' = '14:18
ogra_yeah14:19
apwrtg, there is habit for you14:19
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ckingand it needs to be a power of 2 14:57
henrixrtg: do you remember if chiluk was hitting this issue on T only?15:43
henrixrtg: maybe i discarded these patches from 3.11 stable too early...15:43
henrixalthough the backport could be non-trivial15:44
rtghenrix, pretty sure it was on T15:46
henrixrtg: ack15:46
rtghenrix, I'm not sure those VFS patches would be right for 3.1115:47
henrixrtg: yeah, i dropped them, but i admit i didn't tried too hard to understand the issues they solve... :-/15:48
rtghenrix, it might just be the namespace mount point proliferation problem. I wonder if hallyn would know.15:50
hallyn?15:54
rtghallyn, these commits in 3.14:15:54
rtg38129a1 switch mnt_hash to hlist15:54
rtg 0b1b901 don't bother with propagate_mnt() unless the target is shared15:54
rtg 1d6a32a keep shadowed vfsmounts together15:54
rtg 0818bf2 resizable namespace.c hashes15:54
rtgdo they help the performance of removing mount points ?15:55
hallynsorry i haven't seenthem15:55
hallyncertainly 0b1b901 should15:55
apwrtg, was that arges' bug perhaps15:55
hallynas should the first15:55
rtgapw, I thought it was chiluk ?15:56
apwoh maybe, perhaps i need a beer to remind me15:56
rtgapw, whoa, it _is_ about that time.15:56
ogra_way past 15:57
ogra_*burp*15:57
hallyndrat i'm in the wrong tz15:57
* hallyn swigs some coffee, wishing it were something else15:57
rtghallyn, could you have a look at those commits ? They are scheduled for 3.13 stable, but I might pull them earlier and get some testing on them.15:58
hallynrtg: meeting coming up, i'll look after that15:58
rtghallyn, thanks15:59
hallynnp - ttyl15:59
argeshallyn: apw : yea it was chiluk's bug16:01
chiluk`rtg henriz   0818bf27c05b2   is the important one that should be included in all stable kernels.16:19
chiluk`give me a sec to take a look..16:19
rtgchiluk`, well, its not in Trusty16:20
chiluk`although the move to hlist for m_hash is not necessary16:20
rtgthough it is marked for stable16:21
zequenceNot at all meaning to sound negative, and also, since I'm a fan of you know who, it's SRU up your ass time again!16:35
zequenceinfinity: Any chance you'll be SRU'ing linux-lowlatency at next point release to a newer version? I've been meaning to try make that happen, but perhaps now I don't even need to?16:36
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zequenceJust to clarify, was just quoting Metallica before.16:57
rtgogasawara, contrary to your meeting notes, I _do_ plan to upload once more before freeze, if for no other reason then to remove lttng in favor of the lttng-modules package.17:53
ogasawarartg: oh you do?  when do you think you'll do the upload?17:54
ogasawarartg: tomorrow?17:54
rtgogasawara, I guess it'll have to be tomorrow won't it. Thursday my time would be too late.17:54
ogasawarartg: ok cool, I'll see if I can squeeze in this patch I've been bisecting for17:55
ogasawarartg: just depends on how quickly I can get this testing feedback17:55
rtgogasawara, ack17:55
hallynchiluk: so why is 0818bf27c05b2 important?18:21
hallynit seems to me that commit 38129a1 is important as otherwise we risk infinite loops when racing withumounts (if the description is to be believed)18:22
hallynand commit 1d6a32a seems to be a prereq for that one18:22
chilukhallyn, so openstack neutron nodes keep the network processes in network namespaces and mount namespaces... unfortunately that means that for n network namespaces... there has to be n^2 entries in the mount_hashtable.18:23
hallyncommit 0b1b901 seems unimportant - we only save a lock_mount_hash (and unlock), so unless we are seeing that as a hot path somewhere...18:23
chilukso for 4000 namespaces that means 1.6m entries in that hashtable.18:23
chilukwhich becomes a serious bottleneck, and can also lead to hangs and crashing18:23
hallynchiluk: ok andn so switching to hlist halves the size of that table?18:23
chilukhlist isn't as important as increasing the size of the hashtable itself.18:24
chilukbut hlist would help as well.18:24
hallyni'd be curious to see how much kmem you save then with both  38129a1 and 0b1b90118:24
hallynuh, i mean and 0818bf218:24
hallynchiluk: so you would agree that commit 0b1b901 seems unimportant?18:25
chilukwell since they all are meant to improve the performance of the mount namespaces, I would think they are all important... some more than others.18:26
chiluk0818bf2 should go into all p+ kernels imho18:27
chiluk0818bf2 1d6a32 0b1b901 38129a13 should all go into trusty.18:27
chilukif they don't clean cherry-pick, I'll work on a backport.18:27
sorenchiluk: 4000 network namespaces? Is that a number you're making up or does someone claim to need anything even close to that?19:13
sorenchiluk: It just sounds a bit over the top to me. Even with a 64 CPU system with, say, 8 VM's per CPU, you'd need an average of 8 distinct networks per VM to reach that number.19:14
chiluksoren... look at openstack .. and yes 4000 is only a small part for a decent sized cloud.19:17
chilukit's not the compute nodes that are the problem.19:18
sorenchiluk: Oh, right, the network nodes need to accommodate every single network.19:18
chiluksoren it's the network gateways... mount/net namespaces are used to partition the network by the neutron nodes19:19
sorenchiluk: Gosh, yes, 4000 aren't going to get you anywhere then.19:19
chilukexactly19:19
* soren shakes his head at that horrible design19:19
chilukright now most people scale out their gateways19:19
chilukbut some people have beefy gateways, and are pissed at the 3-4k limitation.19:19
sorenchiluk: Understandable.19:20
sorenchiluk: Yeah, I totally hadn't thought of the network nodes. It makes much more sense that way.19:20
chilukwith these patches those people can take the current 4k hashtable and make it 512mb or more... and get much better performance on deletion..19:21
chilukwhich is usually where the problems started.19:21
chilukit used to be a 4k hashtable with 80k node linked lists... 19:21
sorenOh, it doesn't remove the O(n^2) space complexity?19:22
sorenOh, my.19:22
chilukit does not.19:22
sorenYeah, that sounds like no fun at all.19:22
chilukthe issue with O(n^2) comes from the lack of forsite in the unshare(CLONE_NEWNS) calls19:23
chilukand the fact that each new net namespace creates it's own mount...19:23
chilukfor proc entries.19:23
* soren doesn't quite grok how that becomes an n^2 thing19:24
chilukeach namespace creates a mount... each namespace duplicates all mounts for it's namespace.19:25
sorenOh.19:26
chilukor at least creates duplicate entries in those tables for it'a namespace.19:26
hallynif you're doing network namespaces it's not strictly necessary to have fresh mounts ns in each netns19:42
infinityzequence: You might need to rephrase your question.20:17
zequenceinfinity: are you going to SRU the trusty kernel to precise later?21:02
bjfzequence, if you are asking if there will be an lts-backport-trusty kernel for precise the answer is yes21:03
bjfzequence, that is also why there will be a 12.04.5 release21:03
infinityzequence: However, the answer to the question you were really asking (does linux-lts-trusty include lowlatency) is currently "no".21:06
infinityAnd will probably remain no for that backport.21:07
infinityBut for 14.10 kernels backported to trusty, I think we should enable all flavours.21:07
zequenceinfinity: Alright21:07
gabriellHello. I'm newbie to kernel development. I'm trying to load a module I wrote, but I'm getting the error "Invalid module format". Can anyone help me with this?21:50
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